/***************************************************************************
 *   Copyright (C) 2005 by Enrico Ros <eros.kde@email.it>                  *
 *                                                                         *
 *   This program is free software; you can redistribute it and/or modify  *
 *   it under the terms of the GNU General Public License as published by  *
 *   the Free Software Foundation; either version 2 of the License, or     *
 *   (at your option) any later version.                                   *
 ***************************************************************************/

#include "pagepainter.h"

// qt / kde includes
#include <qrect.h>
#include <qpainter.h>
#include <qpalette.h>
#include <qpixmap.h>
#include <qvarlengtharray.h>
#include <kiconloader.h>
#include <QDebug>
#include <QApplication>
#include <QIcon>
#include <QTransform>

// system includes
#include <math.h>

// local includes
#include "core/area.h"
#include "core/page.h"
#include "core/page_p.h"
#include "core/annotations.h"
#include "core/utils.h"
#include "guiutils.h"
#include "settings.h"
#include "core/observer.h"
#include "core/tile.h"
#include "settings_core.h"
#include "ui/debug_ui.h"

Q_GLOBAL_STATIC_WITH_ARGS( QPixmap, busyPixmap, ( KIconLoader::global()->loadIcon(QLatin1String("okular"), KIconLoader::NoGroup, IconSize(KIconLoader::Desktop), KIconLoader::DefaultState, QStringList(), 0, true) ) )

#define TEXTANNOTATION_ICONSIZE 24

inline QPen buildPen( const Okular::Annotation *ann, double width, const QColor &color )
{
    QPen p(
        QBrush( color ),
        width,
        ann->style().lineStyle() == Okular::Annotation::Dashed ? Qt::DashLine : Qt::SolidLine,
        Qt::SquareCap,
        Qt::MiterJoin
    );
    return p;
}

void PagePainter::paintPageOnPainter( QPainter * destPainter, const Okular::Page * page,
    Okular::DocumentObserver *observer, int flags, int scaledWidth, int scaledHeight, const QRect limits )
{
        paintCroppedPageOnPainter( destPainter, page, observer, flags, scaledWidth, scaledHeight, limits,
                                   Okular::NormalizedRect( 0, 0, 1, 1 ), nullptr );
}

void PagePainter::paintCroppedPageOnPainter( QPainter * destPainter, const Okular::Page * page,
    Okular::DocumentObserver *observer, int flags, int scaledWidth, int scaledHeight, const QRect limits,
    const Okular::NormalizedRect &crop, Okular::NormalizedPoint *viewPortPoint )
{
    qreal dpr = destPainter->device()->devicePixelRatioF();

    /* Calculate the cropped geometry of the page */
    QRect scaledCrop = crop.geometry( scaledWidth, scaledHeight );

    /* variables prefixed with d are in the device pixels coordinate system, which translates to the rendered output - that means,
     * multiplied with the device pixel ratio of the target PaintDevice */
    const QRect dScaledCrop(QRectF(scaledCrop.x() * dpr, scaledCrop.y() * dpr, scaledCrop.width() * dpr, scaledCrop.height() * dpr).toAlignedRect());

    int croppedWidth = scaledCrop.width();
    int croppedHeight = scaledCrop.height();

    int dScaledWidth = ceil(scaledWidth * dpr);
    int dScaledHeight = ceil(scaledHeight * dpr);
    const QRect dLimits(QRectF(limits.x() * dpr, limits.y() * dpr, limits.width() * dpr, limits.height() * dpr).toAlignedRect());

    QColor paperColor = Qt::white;
    QColor backgroundColor = paperColor;
    if ( Okular::SettingsCore::changeColors() )
    {
        switch ( Okular::SettingsCore::renderMode() )
        {
            case Okular::SettingsCore::EnumRenderMode::Inverted:
                backgroundColor = Qt::black;
                break;
            case Okular::SettingsCore::EnumRenderMode::Paper:
                paperColor = Okular::SettingsCore::paperColor();
                backgroundColor = paperColor;
                break;
            case Okular::SettingsCore::EnumRenderMode::Recolor:
                backgroundColor = Okular::Settings::recolorBackground();
                break;
            default: ;
        }
    }
    destPainter->fillRect( limits, backgroundColor );

    const bool hasTilesManager = page->hasTilesManager( observer );
    QPixmap pixmap;

    if ( !hasTilesManager )
    {
        /** 1 - RETRIEVE THE 'PAGE+ID' PIXMAP OR A SIMILAR 'PAGE' ONE **/
        const QPixmap *p = page->_o_nearestPixmap( observer, dScaledWidth, dScaledHeight );

        if (p != nullptr) {
            pixmap = *p;
            pixmap.setDevicePixelRatio( qApp->devicePixelRatio() );
        }

        /** 1B - IF NO PIXMAP, DRAW EMPTY PAGE **/
        double pixmapRescaleRatio = !pixmap.isNull() ? dScaledWidth / (double)pixmap.width() : -1;
        long pixmapPixels = !pixmap.isNull() ? (long)pixmap.width() * (long)pixmap.height() : 0;
        if ( pixmap.isNull() || pixmapRescaleRatio > 20.0 || pixmapRescaleRatio < 0.25 ||
             (dScaledWidth > pixmap.width() && pixmapPixels > 60000000L) )
        {
            // draw something on the blank page: the okular icon or a cross (as a fallback)
            if ( !busyPixmap()->isNull() )
            {
                busyPixmap->setDevicePixelRatio(dpr);
                destPainter->drawPixmap( QPoint( 10, 10 ), *busyPixmap() );
            }
            else
            {
                destPainter->setPen( Qt::gray );
                destPainter->drawLine( 0, 0, croppedWidth-1, croppedHeight-1 );
                destPainter->drawLine( 0, croppedHeight-1, croppedWidth-1, 0 );
            }
            return;
        }
    }

    /** 2 - FIND OUT WHAT TO PAINT (Flags + Configuration + Presence) **/
    bool canDrawHighlights = (flags & Highlights) && !page->m_highlights.isEmpty();
    bool canDrawTextSelection = (flags & TextSelection) && page->textSelection();
    bool canDrawAnnotations = (flags & Annotations) && !page->m_annotations.isEmpty();
    bool enhanceLinks = (flags & EnhanceLinks) && Okular::Settings::highlightLinks();
    bool enhanceImages = (flags & EnhanceImages) && Okular::Settings::highlightImages();

    // vectors containing objects to draw
    // make this a qcolor, rect map, since we don't need
    // to know s_id here! we are only drawing this right?
    QList< QPair<QColor, Okular::NormalizedRect> > * bufferedHighlights = nullptr;
    QList< Okular::Annotation * > * bufferedAnnotations = nullptr;
    QList< Okular::Annotation * > * unbufferedAnnotations = nullptr;
    Okular::Annotation *boundingRectOnlyAnn = nullptr; // Paint the bounding rect of this annotation
    // fill up lists with visible annotation/highlight objects/text selections
    if ( canDrawHighlights || canDrawTextSelection || canDrawAnnotations )
    {
        // precalc normalized 'limits rect' for intersection
        double nXMin = ( (double)limits.left() / scaledWidth ) + crop.left,
               nXMax = ( (double)limits.right() / scaledWidth )  + crop.left,
               nYMin = ( (double)limits.top() / scaledHeight ) + crop.top,
               nYMax = ( (double)limits.bottom() / scaledHeight ) + crop.top;
        // append all highlights inside limits to their list
        if ( canDrawHighlights )
        {
            if ( !bufferedHighlights )
                 bufferedHighlights = new QList< QPair<QColor, Okular::NormalizedRect> >();
/*            else
            {*/
                
                Okular::NormalizedRect* limitRect = new Okular::NormalizedRect(nXMin, nYMin, nXMax, nYMax );
                QLinkedList< Okular::HighlightAreaRect * >::const_iterator h2It = page->m_highlights.constBegin(), hEnd = page->m_highlights.constEnd();
                Okular::HighlightAreaRect::const_iterator hIt;
                for ( ; h2It != hEnd; ++h2It )
                    for (hIt=(*h2It)->constBegin(); hIt!=(*h2It)->constEnd(); ++hIt)
                    {
                        if ((*hIt).intersects(limitRect))
                            bufferedHighlights->append( qMakePair((*h2It)->color,*hIt) );
                    }
                delete limitRect;
            //}
        }
        if ( canDrawTextSelection )
        {
            if ( !bufferedHighlights )
                 bufferedHighlights = new QList< QPair<QColor, Okular::NormalizedRect>  >();
/*            else
            {*/
                Okular::NormalizedRect* limitRect = new Okular::NormalizedRect(nXMin, nYMin, nXMax, nYMax );
                const Okular::RegularAreaRect *textSelection = page->textSelection();
                Okular::HighlightAreaRect::const_iterator hIt = textSelection->constBegin(), hEnd = textSelection->constEnd();
                for ( ; hIt != hEnd; ++hIt )
                {
                    if ( (*hIt).intersects( limitRect ) )
                        bufferedHighlights->append( qMakePair( page->textSelectionColor(), *hIt ) );
                }
                delete limitRect;
            //}
        }
        // append annotations inside limits to the un/buffered list
        if ( canDrawAnnotations )
        {
            QLinkedList< Okular::Annotation * >::const_iterator aIt = page->m_annotations.constBegin(), aEnd = page->m_annotations.constEnd();
            for ( ; aIt != aEnd; ++aIt )
            {
                Okular::Annotation * ann = *aIt;
                int flags = ann->flags();

                if ( flags & Okular::Annotation::Hidden )
                    continue;

                if ( flags & Okular::Annotation::ExternallyDrawn )
                {
                    // ExternallyDrawn annots are never rendered by PagePainter.
                    // Just paint the boundingRect if the annot is moved or resized.
                    if ( flags & (Okular::Annotation::BeingMoved | Okular::Annotation::BeingResized) )
                    {
                        boundingRectOnlyAnn = ann;
                    }
                    continue;
                }

                bool intersects = ann->transformedBoundingRectangle().intersects( nXMin, nYMin, nXMax, nYMax );
                if ( ann->subType() == Okular::Annotation::AText )
                {
                    Okular::TextAnnotation * ta = static_cast< Okular::TextAnnotation * >( ann );
                    if ( ta->textType() == Okular::TextAnnotation::Linked )
                    {
                        Okular::NormalizedRect iconrect( ann->transformedBoundingRectangle().left,
                                                         ann->transformedBoundingRectangle().top,
                                                         ann->transformedBoundingRectangle().left + TEXTANNOTATION_ICONSIZE / page->width(),
                                                         ann->transformedBoundingRectangle().top + TEXTANNOTATION_ICONSIZE / page->height() );
                        intersects = iconrect.intersects( nXMin, nYMin, nXMax, nYMax );
                    }
                }
                if ( intersects )
                {
                    Okular::Annotation::SubType type = ann->subType();
                    if ( type == Okular::Annotation::ALine || type == Okular::Annotation::AHighlight ||
                         type == Okular::Annotation::AInk  /*|| (type == Annotation::AGeom && ann->style().opacity() < 0.99)*/ )
                    {
                        if ( !bufferedAnnotations )
                            bufferedAnnotations = new QList< Okular::Annotation * >();
                        bufferedAnnotations->append( ann );
                    }
                    else
                    {
                        if ( !unbufferedAnnotations )
                            unbufferedAnnotations = new QList< Okular::Annotation * >();
                        unbufferedAnnotations->append( ann );
                    }
                }
            }
        }
        // end of intersections checking
    }

    /** 3 - ENABLE BACKBUFFERING IF DIRECT IMAGE MANIPULATION IS NEEDED **/
    bool bufferAccessibility = (flags & Accessibility) && Okular::SettingsCore::changeColors() && (Okular::SettingsCore::renderMode() != Okular::SettingsCore::EnumRenderMode::Paper);
    bool useBackBuffer = bufferAccessibility || bufferedHighlights || bufferedAnnotations || viewPortPoint;
    QPixmap * backPixmap = nullptr;
    QPainter * mixedPainter = nullptr;
    QRect limitsInPixmap = limits.translated( scaledCrop.topLeft() );
    QRect dLimitsInPixmap = dLimits.translated( dScaledCrop.topLeft() );

        // limits within full (scaled but uncropped) pixmap

    /** 4A -- REGULAR FLOW. PAINT PIXMAP NORMAL OR RESCALED USING GIVEN QPAINTER **/
    if ( !useBackBuffer )
    {
        if ( hasTilesManager )
        {
            const Okular::NormalizedRect normalizedLimits( limitsInPixmap, scaledWidth, scaledHeight );
            const QList<Okular::Tile> tiles = page->tilesAt( observer, normalizedLimits );
            QList<Okular::Tile>::const_iterator tIt = tiles.constBegin(), tEnd = tiles.constEnd();
            while ( tIt != tEnd )
            {
                const Okular::Tile &tile = *tIt;
                QRect tileRect = tile.rect().geometry( scaledWidth, scaledHeight ).translated( -scaledCrop.topLeft() );
                QRect dTileRect = QRectF(tileRect.x() * dpr, tileRect.y() * dpr, tileRect.width() * dpr, tileRect.height() * dpr).toAlignedRect();
                QRect limitsInTile = limits & tileRect;
                QRectF dLimitsInTile = dLimits & dTileRect;

                if ( !limitsInTile.isEmpty() )
                {
                    QPixmap* tilePixmap = tile.pixmap();
                    tilePixmap->setDevicePixelRatio( qApp->devicePixelRatio() );

                    if ( tilePixmap->width() == dTileRect.width() && tilePixmap->height() == dTileRect.height() ) {
                        destPainter->drawPixmap( limitsInTile.topLeft(), *tilePixmap,
                                dLimitsInTile.translated( -dTileRect.topLeft() ) );
                    } else {
                        destPainter->drawPixmap( tileRect, *tilePixmap );
                    }
                }
                tIt++;
            }
        }
        else
        {
            QPixmap scaledCroppedPixmap = pixmap.scaled(dScaledWidth, dScaledHeight).copy(dLimitsInPixmap);
            scaledCroppedPixmap.setDevicePixelRatio(dpr);
            destPainter->drawPixmap( limits.topLeft(), scaledCroppedPixmap, QRectF(0, 0, dLimits.width(),dLimits.height()));
        }

        // 4A.2. active painter is the one passed to this method
        mixedPainter = destPainter;
    }
    /** 4B -- BUFFERED FLOW. IMAGE PAINTING + OPERATIONS. QPAINTER OVER PIXMAP  **/
    else
    {
        // the image over which we are going to draw
        QImage backImage = QImage( dLimits.width(), dLimits.height(), QImage::Format_ARGB32_Premultiplied );
        backImage.setDevicePixelRatio(dpr);
        backImage.fill( paperColor );
        QPainter p( &backImage );

        if ( hasTilesManager )
        {
            const Okular::NormalizedRect normalizedLimits( limitsInPixmap, scaledWidth, scaledHeight );
            const QList<Okular::Tile> tiles = page->tilesAt( observer, normalizedLimits );
            QList<Okular::Tile>::const_iterator tIt = tiles.constBegin(), tEnd = tiles.constEnd();
            while ( tIt != tEnd )
            {
                const Okular::Tile &tile = *tIt;
                QRect tileRect = tile.rect().geometry( scaledWidth, scaledHeight ).translated( -scaledCrop.topLeft() );
                QRect dTileRect(QRectF(tileRect.x() * dpr, tileRect.y() * dpr, tileRect.width() * dpr, tileRect.height() * dpr).toAlignedRect());
                QRect limitsInTile = limits & tileRect;
                QRect dLimitsInTile = dLimits & dTileRect;

                if ( !limitsInTile.isEmpty() )
                {
                    QPixmap* tilePixmap = tile.pixmap();
                    tilePixmap->setDevicePixelRatio( qApp->devicePixelRatio() );

                    if ( tilePixmap->width() == dTileRect.width() && tilePixmap->height() == dTileRect.height() )
                    {
                        p.drawPixmap( limitsInTile.translated( -limits.topLeft() ).topLeft(), *tilePixmap,
                                dLimitsInTile.translated( -dTileRect.topLeft() ) );
                    }
                    else
                    {
                        double xScale = tilePixmap->width() / (double)dTileRect.width();
                        double yScale = tilePixmap->height() / (double)dTileRect.height();
                        QTransform transform( xScale, 0, 0, yScale, 0, 0 );
                        p.drawPixmap( limitsInTile.translated( -limits.topLeft() ), *tilePixmap,
                                transform.mapRect( dLimitsInTile ).translated( -transform.mapRect( dTileRect ).topLeft() ) );
                    }
                }
                ++tIt;
            }
        }
        else
        {
            // 4B.1. draw the page pixmap: normal or scaled
            QPixmap scaledCroppedPixmap = pixmap.scaled(dScaledWidth, dScaledHeight).copy(dLimitsInPixmap);
            scaledCroppedPixmap.setDevicePixelRatio(dpr);
            p.drawPixmap( 0, 0, scaledCroppedPixmap );
        }

        p.end();

        // 4B.2. modify pixmap following accessibility settings
        if ( bufferAccessibility )
        {
            switch ( Okular::SettingsCore::renderMode() )
            {
                case Okular::SettingsCore::EnumRenderMode::Inverted:
                    // Invert image pixels using QImage internal function
                    backImage.invertPixels(QImage::InvertRgb);
                    break;
                case Okular::SettingsCore::EnumRenderMode::Recolor:
                    recolor(&backImage, Okular::Settings::recolorForeground(), Okular::Settings::recolorBackground());
                    break;
                case Okular::SettingsCore::EnumRenderMode::BlackWhite:
                    blackWhite(&backImage, Okular::Settings::bWContrast(), Okular::Settings::bWThreshold());
                    break;
                case Okular::SettingsCore::EnumRenderMode::InvertLightness:
                    invertLightness(&backImage);
                    break;
                case Okular::SettingsCore::EnumRenderMode::InvertLuma:
                    invertLuma(&backImage, 0.2126, 0.7152, 0.0722); // sRGB / Rec. 709 luma coefficients
                    break;
                case Okular::SettingsCore::EnumRenderMode::InvertLumaSymmetric:
                    invertLuma(&backImage, 0.3333, 0.3334, 0.3333); // Symmetric coefficients, to keep colors saturated.
                    break;
                case Okular::SettingsCore::EnumRenderMode::HueShiftPositive:
                    hueShiftPositive(&backImage);
                    break;
                case Okular::SettingsCore::EnumRenderMode::HueShiftNegative:
                    hueShiftNegative(&backImage);
                    break;
            }
        }

        // 4B.3. highlight rects in page
        if ( bufferedHighlights )
        {
            // draw highlights that are inside the 'limits' paint region
            for (const auto& highlight : qAsConst(*bufferedHighlights))
            {
                const Okular::NormalizedRect & r = highlight.second;
                // find out the rect to highlight on pixmap
                QRect highlightRect = r.geometry( scaledWidth, scaledHeight ).translated( -scaledCrop.topLeft() ).intersected( limits );
                highlightRect.translate( -limits.left(), -limits.top() );

                const QColor highlightColor = highlight.first;
                QPainter painter(&backImage);
                painter.setCompositionMode(QPainter::CompositionMode_Multiply);
                painter.fillRect(highlightRect, highlightColor);

                auto frameColor = highlightColor.darker(150);
                const QRect frameRect = r.geometry( scaledWidth, scaledHeight ).translated( -scaledCrop.topLeft() ).translated( -limits.left(), -limits.top() );
                painter.setPen(frameColor);
                painter.drawRect(frameRect);
            }
        }

        // 4B.4. paint annotations [COMPOSITED ONES]
        if ( bufferedAnnotations )
        {
            // Albert: This is quite "heavy" but all the backImage that reach here are QImage::Format_ARGB32_Premultiplied
            // and have to be so that the QPainter::CompositionMode_Multiply works
            // we could also put a
            // backImage = backImage.convertToFormat(QImage::Format_ARGB32_Premultiplied)
            // that would be almost a noop, but we'll leave the assert for now
            Q_ASSERT(backImage.format() == QImage::Format_ARGB32_Premultiplied);
            // precalc constants for normalizing [0,1] page coordinates into normalized [0,1] limit rect coordinates
            double pageScale = (double)croppedWidth / page->width();
            double xOffset = (double)limits.left() / (double)scaledWidth + crop.left,
                   xScale = (double)scaledWidth / (double)limits.width(),
                   yOffset = (double)limits.top() / (double)scaledHeight + crop.top,
                   yScale = (double)scaledHeight / (double)limits.height();

            // paint all buffered annotations in the page
            QList< Okular::Annotation * >::const_iterator aIt = bufferedAnnotations->constBegin(), aEnd = bufferedAnnotations->constEnd();
            for ( ; aIt != aEnd; ++aIt )
            {
                Okular::Annotation * a = *aIt;
                Okular::Annotation::SubType type = a->subType();
                QColor acolor = a->style().color();
                if ( !acolor.isValid() )
                    acolor = Qt::yellow;
                acolor.setAlphaF( a->style().opacity() );

                // draw LineAnnotation MISSING: caption, dash pattern, endings for multipoint lines
                if ( type == Okular::Annotation::ALine )
                {
                    LineAnnotPainter linepainter { (Okular::LineAnnotation *) a,
                        { page->width(), page->height() }, pageScale,
                        { xScale, 0., 0., yScale, -xOffset * xScale, -yOffset * yScale } };
                    linepainter.draw( backImage );
                }
                // draw HighlightAnnotation MISSING: under/strike width, feather, capping
                else if ( type == Okular::Annotation::AHighlight )
                {
                    // get the annotation
                    Okular::HighlightAnnotation * ha = (Okular::HighlightAnnotation *) a;
                    Okular::HighlightAnnotation::HighlightType type = ha->highlightType();

                    // draw each quad of the annotation
                    int quads = ha->highlightQuads().size();
                    for ( int q = 0; q < quads; q++ )
                    {
                        NormalizedPath path;
                        const Okular::HighlightAnnotation::Quad & quad = ha->highlightQuads()[ q ];
                        // normalize page point to image
                        for ( int i = 0; i < 4; i++ )
                        {
                            Okular::NormalizedPoint point;
                            point.x = (quad.transformedPoint( i ).x - xOffset) * xScale;
                            point.y = (quad.transformedPoint( i ).y - yOffset) * yScale;
                            path.append( point );
                        }
                        // draw the normalized path into image
                        switch ( type )
                        {
                            // highlight the whole rect
                            case Okular::HighlightAnnotation::Highlight:
                                drawShapeOnImage( backImage, path, true, Qt::NoPen, acolor, pageScale, Multiply );
                                break;
                            // highlight the bottom part of the rect
                            case Okular::HighlightAnnotation::Squiggly:
                                path[ 3 ].x = ( path[ 0 ].x + path[ 3 ].x ) / 2.0;
                                path[ 3 ].y = ( path[ 0 ].y + path[ 3 ].y ) / 2.0;
                                path[ 2 ].x = ( path[ 1 ].x + path[ 2 ].x ) / 2.0;
                                path[ 2 ].y = ( path[ 1 ].y + path[ 2 ].y ) / 2.0;
                                drawShapeOnImage( backImage, path, true, Qt::NoPen, acolor, pageScale, Multiply );
                                break;
                            // make a line at 3/4 of the height
                            case Okular::HighlightAnnotation::Underline:
                                path[ 0 ].x = ( 3 * path[ 0 ].x + path[ 3 ].x ) / 4.0;
                                path[ 0 ].y = ( 3 * path[ 0 ].y + path[ 3 ].y ) / 4.0;
                                path[ 1 ].x = ( 3 * path[ 1 ].x + path[ 2 ].x ) / 4.0;
                                path[ 1 ].y = ( 3 * path[ 1 ].y + path[ 2 ].y ) / 4.0;
                                path.pop_back();
                                path.pop_back();
                                drawShapeOnImage( backImage, path, false, QPen( acolor, 2 ), QBrush(), pageScale );
                                break;
                            // make a line at 1/2 of the height
                            case Okular::HighlightAnnotation::StrikeOut:
                                path[ 0 ].x = ( path[ 0 ].x + path[ 3 ].x ) / 2.0;
                                path[ 0 ].y = ( path[ 0 ].y + path[ 3 ].y ) / 2.0;
                                path[ 1 ].x = ( path[ 1 ].x + path[ 2 ].x ) / 2.0;
                                path[ 1 ].y = ( path[ 1 ].y + path[ 2 ].y ) / 2.0;
                                path.pop_back();
                                path.pop_back();
                                drawShapeOnImage( backImage, path, false, QPen( acolor, 2 ), QBrush(), pageScale );
                                break;
                        }
                    }
                }
                // draw InkAnnotation MISSING:invar width, PENTRACER
                else if ( type == Okular::Annotation::AInk )
                {
                    // get the annotation
                    Okular::InkAnnotation * ia = (Okular::InkAnnotation *) a;

                    // draw each ink path
                    const QList< QLinkedList<Okular::NormalizedPoint> > transformedInkPaths = ia->transformedInkPaths();

                    const QPen inkPen = buildPen( a, a->style().width(), acolor );

                    int paths = transformedInkPaths.size();
                    for ( int p = 0; p < paths; p++ )
                    {
                        NormalizedPath path;
                        const QLinkedList<Okular::NormalizedPoint> & inkPath = transformedInkPaths[ p ];

                        // normalize page point to image
                        QLinkedList<Okular::NormalizedPoint>::const_iterator pIt = inkPath.constBegin(), pEnd = inkPath.constEnd();
                        for ( ; pIt != pEnd; ++pIt )
                        {
                            const Okular::NormalizedPoint & inkPoint = *pIt;
                            Okular::NormalizedPoint point;
                            point.x = (inkPoint.x - xOffset) * xScale;
                            point.y = (inkPoint.y - yOffset) * yScale;
                            path.append( point );
                        }
                        // draw the normalized path into image
                        drawShapeOnImage( backImage, path, false, inkPen, QBrush(), pageScale );
                    }
                }
            } // end current annotation drawing
        }
        if(viewPortPoint)
        {
            QPainter painter(&backImage);
            painter.translate( -limits.left(), -limits.top() );
            painter.setPen( QApplication::palette().color( QPalette::Active, QPalette::Highlight ) );
            painter.drawLine( 0, viewPortPoint->y * scaledHeight + 1, scaledWidth - 1, viewPortPoint->y * scaledHeight + 1 );
// ROTATION CURRENTLY NOT IMPLEMENTED
/*
            if( page->rotation() == Okular::Rotation0)
            {

            }
            else if(page->rotation() == Okular::Rotation270)
            {
                painter.drawLine( viewPortPoint->y * scaledHeight + 1, 0, viewPortPoint->y * scaledHeight + 1, scaledWidth - 1);
            }
            else if(page->rotation() == Okular::Rotation180)
            {
                painter.drawLine( 0, (1.0 - viewPortPoint->y) * scaledHeight - 1, scaledWidth - 1, (1.0 - viewPortPoint->y) * scaledHeight - 1 );
            }
            else if(page->rotation() == Okular::Rotation90) // not right, rotation clock-wise
            {
                painter.drawLine( scaledWidth - (viewPortPoint->y * scaledHeight + 1), 0, scaledWidth - (viewPortPoint->y * scaledHeight + 1), scaledWidth - 1);
            }
*/
        }

        // 4B.5. create the back pixmap converting from the local image
        backPixmap = new QPixmap( QPixmap::fromImage( backImage ) );
        backPixmap->setDevicePixelRatio(dpr);

        // 4B.6. create a painter over the pixmap and set it as the active one
        mixedPainter = new QPainter( backPixmap );
        mixedPainter->translate( -limits.left(), -limits.top() );
    }

    /** 5 -- MIXED FLOW. Draw ANNOTATIONS [OPAQUE ONES] on ACTIVE PAINTER  **/
    if ( unbufferedAnnotations )
    {
        // iterate over annotations and paint AText, AGeom, AStamp
        QList< Okular::Annotation * >::const_iterator aIt = unbufferedAnnotations->constBegin(), aEnd = unbufferedAnnotations->constEnd();
        for ( ; aIt != aEnd; ++aIt )
        {
            Okular::Annotation * a = *aIt;

            // honor opacity settings on supported types
            unsigned int opacity = (unsigned int)( a->style().color().alpha() * a->style().opacity() );
            // skip the annotation drawing if all the annotation is fully
            // transparent, but not with text annotations
            if ( opacity <= 0 && a->subType() != Okular::Annotation::AText )
                continue;

            QColor acolor = a->style().color();
            if ( !acolor.isValid() )
                acolor = Qt::yellow;
            acolor.setAlpha( opacity );

            // get annotation boundary and drawn rect
            QRect annotBoundary = a->transformedBoundingRectangle().geometry( scaledWidth, scaledHeight ).translated( -scaledCrop.topLeft() );
            QRect annotRect = annotBoundary.intersected( limits );
            QRect innerRect( annotRect.left() - annotBoundary.left(), annotRect.top() -
                    annotBoundary.top(), annotRect.width(), annotRect.height() );
            QRectF dInnerRect(innerRect.x() * dpr, innerRect.y() * dpr, innerRect.width() * dpr, innerRect.height() * dpr);

            Okular::Annotation::SubType type = a->subType();

            // draw TextAnnotation
            if ( type == Okular::Annotation::AText )
            {
                Okular::TextAnnotation * text = (Okular::TextAnnotation *)a;
                if ( text->textType() == Okular::TextAnnotation::InPlace )
                {
                    QImage image( annotBoundary.size(), QImage::Format_ARGB32 );
                    image.fill( acolor.rgba() );
                    QPainter painter( &image );
                    painter.setFont( text->textFont() );
                    painter.setPen( text->textColor() );
                    Qt::AlignmentFlag halign = ( text->inplaceAlignment() == 1 ? Qt::AlignHCenter : ( text->inplaceAlignment() == 2 ? Qt::AlignRight : Qt::AlignLeft ) );
                    const double invXScale = (double)page->width() / scaledWidth;
                    const double invYScale = (double)page->height() / scaledHeight;
                    const double borderWidth = text->style().width();
                    painter.scale( 1 / invXScale, 1 / invYScale );
                    painter.drawText( borderWidth * invXScale, borderWidth * invYScale,
                                      (image.width() - 2 * borderWidth) * invXScale,
                                      (image.height() - 2 * borderWidth) * invYScale,
                                      Qt::AlignTop | halign | Qt::TextWordWrap,
                                      text->contents() );
                    painter.resetTransform();
                    //Required as asking for a zero width pen results
                    //in a default width pen (1.0) being created
                    if ( borderWidth != 0 )
                    {
                        QPen pen( Qt::black, borderWidth );
                        painter.setPen( pen );
                        painter.drawRect( 0, 0, image.width() - 1, image.height() - 1 );
                    }
                    painter.end();

                    mixedPainter->drawImage( annotBoundary.topLeft(), image );
                }
                else if ( text->textType() == Okular::TextAnnotation::Linked )
                {
                // get pixmap, colorize and alpha-blend it
                    QString path;
                    QPixmap pixmap = GuiUtils::iconLoader()->loadIcon( text->textIcon().toLower(), KIconLoader::User, 32, KIconLoader::DefaultState, QStringList(), &path, true );
                    if ( path.isEmpty() )
                        pixmap = GuiUtils::iconLoader()->loadIcon( text->textIcon().toLower(), KIconLoader::NoGroup, 32 );

                    QPixmap scaledCroppedPixmap = pixmap.scaled(TEXTANNOTATION_ICONSIZE * dpr, TEXTANNOTATION_ICONSIZE * dpr).copy(dInnerRect.toAlignedRect());
                    scaledCroppedPixmap.setDevicePixelRatio(dpr);
                    QImage scaledCroppedImage = scaledCroppedPixmap.toImage();

                    // if the annotation color is valid (ie it was set), then
                    // use it to colorize the icon, otherwise the icon will be
                    // "gray"
                    if ( a->style().color().isValid() )
                        GuiUtils::colorizeImage( scaledCroppedImage, a->style().color(), opacity );
                    pixmap = QPixmap::fromImage( scaledCroppedImage );

                    // draw the mangled image to painter
                    mixedPainter->drawPixmap( annotRect.topLeft(), pixmap);
                }

            }
            // draw StampAnnotation
            else if ( type == Okular::Annotation::AStamp )
            {
                Okular::StampAnnotation * stamp = (Okular::StampAnnotation *)a;

                // get pixmap and alpha blend it if needed
                QPixmap pixmap = GuiUtils::loadStamp( stamp->stampIconName(), annotBoundary.width() );
                if ( !pixmap.isNull() ) // should never happen but can happen on huge sizes
                {
                    const QRect dInnerRect(QRectF(innerRect.x() * dpr, innerRect.y() * dpr, innerRect.width() * dpr, innerRect.height() * dpr).toAlignedRect());

                    QPixmap scaledCroppedPixmap = pixmap.scaled(annotBoundary.width() * dpr, annotBoundary.height() * dpr).copy(dInnerRect);
                    scaledCroppedPixmap.setDevicePixelRatio(dpr);

                    QImage scaledCroppedImage = scaledCroppedPixmap.toImage();

                    if ( opacity < 255 )
                        changeImageAlpha( scaledCroppedImage, opacity );
                    pixmap = QPixmap::fromImage( scaledCroppedImage );

                    // draw the scaled and al
                    mixedPainter->drawPixmap( annotRect.topLeft(), pixmap );
                }
            }
            // draw GeomAnnotation
            else if ( type == Okular::Annotation::AGeom )
            {
                Okular::GeomAnnotation * geom = (Okular::GeomAnnotation *)a;
                // check whether there's anything to draw
                if ( geom->style().width() || geom->geometricalInnerColor().isValid() )
                {
                    mixedPainter->save();
                    const double width = geom->style().width() * Okular::Utils::realDpi(nullptr).width() / ( 72.0 * 2.0 ) * scaledWidth / page->width();
                    QRectF r( .0, .0, annotBoundary.width(), annotBoundary.height() );
                    r.adjust( width, width, -width, -width );
                    r.translate( annotBoundary.topLeft() );
                    if ( geom->geometricalInnerColor().isValid() )
                    {
                        r.adjust( width, width, -width, -width );
                        const QColor color = geom->geometricalInnerColor();
                        mixedPainter->setPen( Qt::NoPen );
                        mixedPainter->setBrush( QColor( color.red(), color.green(), color.blue(), opacity ) );
                        if ( geom->geometricalType() == Okular::GeomAnnotation::InscribedSquare )
                            mixedPainter->drawRect( r );
                        else
                            mixedPainter->drawEllipse( r );
                        r.adjust( -width, -width, width, width );
                    }
                    if ( geom->style().width() ) // need to check the original size here..
                    {
                        mixedPainter->setPen( buildPen( a, width * 2, acolor ) );
                        mixedPainter->setBrush( Qt::NoBrush );
                        if ( geom->geometricalType() == Okular::GeomAnnotation::InscribedSquare )
                            mixedPainter->drawRect( r );
                        else
                            mixedPainter->drawEllipse( r );
                    }
                    mixedPainter->restore();
                }
            }

            // draw extents rectangle
            if ( Okular::Settings::debugDrawAnnotationRect() )
            {
                mixedPainter->setPen( a->style().color() );
                mixedPainter->drawRect( annotBoundary );
            }
        }
    }

    if ( boundingRectOnlyAnn )
    {
        QRect annotBoundary = boundingRectOnlyAnn->transformedBoundingRectangle().geometry( scaledWidth, scaledHeight ).translated( -scaledCrop.topLeft() );
        mixedPainter->setPen( Qt::DashLine );
        mixedPainter->drawRect( annotBoundary );
    }

    /** 6 -- MIXED FLOW. Draw LINKS+IMAGES BORDER on ACTIVE PAINTER  **/
    if ( enhanceLinks || enhanceImages )
    {
        mixedPainter->save();
        mixedPainter->scale( scaledWidth, scaledHeight );
        mixedPainter->translate( -crop.left, -crop.top );

        QColor normalColor = QApplication::palette().color( QPalette::Active, QPalette::Highlight );
        // enlarging limits for intersection is like growing the 'rectGeometry' below
        QRect limitsEnlarged = limits;
        limitsEnlarged.adjust( -2, -2, 2, 2 );
        // draw rects that are inside the 'limits' paint region as opaque rects
        QLinkedList< Okular::ObjectRect * >::const_iterator lIt = page->m_rects.constBegin(), lEnd = page->m_rects.constEnd();
        for ( ; lIt != lEnd; ++lIt )
        {
            Okular::ObjectRect * rect = *lIt;
            if ( (enhanceLinks && rect->objectType() == Okular::ObjectRect::Action) ||
                 (enhanceImages && rect->objectType() == Okular::ObjectRect::Image) )
            {
                if ( limitsEnlarged.intersects( rect->boundingRect( scaledWidth, scaledHeight ).translated( -scaledCrop.topLeft() ) ) )
                {
                    mixedPainter->strokePath( rect->region(), QPen( normalColor, 0 ) );
                }
            }
        }
        mixedPainter->restore();
    }

    /** 7 -- BUFFERED FLOW. Copy BACKPIXMAP on DESTINATION PAINTER **/
    if ( useBackBuffer )
    {
        delete mixedPainter;
        destPainter->drawPixmap( limits.left(), limits.top(), *backPixmap );
        delete backPixmap;
    }

    // delete object containers
    delete bufferedHighlights;
    delete bufferedAnnotations;
    delete unbufferedAnnotations;
}


/** Private Helpers :: Pixmap conversion **/
void PagePainter::cropPixmapOnImage( QImage & dest, const QPixmap * src, const QRect r )
{
    qreal dpr = src->devicePixelRatioF();

    // handle quickly the case in which the whole pixmap has to be converted
    if ( r == QRect( 0, 0, src->width() / dpr, src->height() / dpr ) )
    {
        dest = src->toImage();
        dest = dest.convertToFormat(QImage::Format_ARGB32_Premultiplied);
    }
    // else copy a portion of the src to an internal pixmap (smaller) and convert it
    else
    {
        QImage croppedImage( r.width() * dpr, r.height() * dpr, QImage::Format_ARGB32_Premultiplied );
        croppedImage.setDevicePixelRatio(dpr);
        QPainter p( &croppedImage );
        p.drawPixmap( 0, 0, *src, r.left(), r.top(), r.width(), r.height() );
        p.end();
        dest = croppedImage;
    }
}

void PagePainter::recolor(QImage *image, const QColor &foreground, const QColor &background)
{
    if (image->format() != QImage::Format_ARGB32_Premultiplied) {
        qCWarning(OkularUiDebug) << "Wrong image format! Converting...";
        *image = image->convertToFormat(QImage::Format_ARGB32_Premultiplied);
    }

    Q_ASSERT(image->format() == QImage::Format_ARGB32_Premultiplied);

    const float scaleRed = background.redF() - foreground.redF();
    const float scaleGreen = background.greenF() - foreground.greenF();
    const float scaleBlue = background.blueF() - foreground.blueF();

    for (int y=0; y<image->height(); y++) {
        QRgb *pixels = reinterpret_cast<QRgb*>(image->scanLine(y));

        for (int x=0; x<image->width(); x++) {
            const int lightness = qGray(pixels[x]);
            pixels[x] = qRgba(scaleRed * lightness + foreground.red(),
                           scaleGreen * lightness + foreground.green(),
                           scaleBlue * lightness + foreground.blue(),
                           qAlpha(pixels[x]));
        }
    }
}

void PagePainter::blackWhite(QImage *image, int contrast, int threshold)
{
    unsigned int * data = reinterpret_cast<unsigned int *>(image->bits());
    int con = contrast;
    int thr = 255 - threshold;

    int pixels = image->width() * image->height();
    for ( int i = 0; i < pixels; ++i )
    {
        // Piecewise linear function of val, through (0, 0), (thr, 128), (255, 255)
        int val = qGray( data[i] );
        if ( val > thr )
            val = 128 + (127 * (val - thr)) / (255 - thr);
        else if ( val < thr )
            val = (128 * val) / thr;

        // Linear contrast stretching through (thr, thr)
        if ( con > 2 )
        {
            val = thr + ( val - thr ) * con / 2;
            val = qBound( 0, val, 255 );
        }
        data[i] = qRgba( val, val, val, 255 );
    }
}

void PagePainter::invertLightness(QImage* image)
{
    if (image->format() != QImage::Format_ARGB32_Premultiplied) {
        qCWarning(OkularUiDebug) << "Wrong image format! Converting...";
        *image = image->convertToFormat(QImage::Format_ARGB32_Premultiplied);
    }

    Q_ASSERT(image->format() == QImage::Format_ARGB32_Premultiplied);

    QRgb * data = reinterpret_cast<QRgb*>(image->bits());
    int pixels = image->width() * image->height();
    for ( int i = 0; i < pixels; ++i )
    {
        // Invert lightness of the pixel using the cylindric HSL color model.
        // Algorithm is based on https://en.wikipedia.org/wiki/HSL_and_HSV#HSL_to_RGB (2019-03-17).
        // Important simplifications are that inverting lightness does not change chroma and hue.
        // This means the sector (of the chroma/hue plane) is not changed,
        // so we can use a linear calculation after determining the sector using qMin() and qMax().
        uchar R = qRed( data[ i ] );
        uchar G = qGreen( data[ i ] );
        uchar B = qBlue( data[ i ] );

        // Get only the needed HSL components. These are chroma C and the common component m.
        // Get common component m
        uchar m = qMin( R, qMin( G, B ) );
        // Remove m from color components
        R -= m;
        G -= m;
        B -= m;
        // Get chroma C
        uchar C = qMax( R, qMax( G, B ) );

        // Get common component m' after inverting lightness L.
        // Hint: Lightness L = m + C / 2; L' = 255 - L = 255 - (m + C / 2) => m' = 255 - C - m
        uchar m_ = 255 - C - m;

        // Add m' to color compontents
        R += m_;
        G += m_;
        B += m_;

        // Save new color
        data[i] = qRgba( R, G, B, 255 );
    }
}

void PagePainter::invertLuma(QImage* image, float Y_R, float Y_G, float Y_B)
{
    if (image->format() != QImage::Format_ARGB32_Premultiplied) {
        qCWarning(OkularUiDebug) << "Wrong image format! Converting...";
        *image = image->convertToFormat(QImage::Format_ARGB32_Premultiplied);
    }

    Q_ASSERT(image->format() == QImage::Format_ARGB32_Premultiplied);

    QRgb * data = reinterpret_cast<QRgb*>(image->bits());
    int pixels = image->width() * image->height();
    for ( int i = 0; i < pixels; ++i )
    {
        uchar R = qRed( data[ i ] );
        uchar G = qGreen( data[ i ] );
        uchar B = qBlue( data[ i ] );

        invertLumaPixel(R, G, B, Y_R, Y_G, Y_B);

        // Save new color
        data[i] = qRgba( R, G, B, 255 );
    }
}

void PagePainter::invertLumaPixel(uchar &R, uchar &G, uchar &B, float Y_R, float Y_G, float Y_B) {
    // Invert luma of the pixel using the bicone HCY color model, stretched to cylindric HSY.
    // Algorithm is based on https://en.wikipedia.org/wiki/HSL_and_HSV#Luma,_chroma_and_hue_to_RGB (2019-03-19).
    // For an illustration see https://experilous.com/1/product/make-it-colorful/ (2019-03-19).

    // Special case: The algorithm does not work when hue is undefined.
    if (R == G && G == B) {
        R = 255 - R;
        G = 255 - G;
        B = 255 - B;
        return;
    }

    // Get input and output luma Y, Y_inv in range 0..255
    float Y = R * Y_R + G * Y_G + B * Y_B;
    float Y_inv = 255 - Y;

    // Get common component m and remove from color components.
    // This moves us to the bottom faces of the HCY bicone, i. e. we get C and X in R, G, B.
    uint_fast8_t m = qMin( R, qMin( G, B ) );
    R -= m;
    G -= m;
    B -= m;

    // We operate in a hue plane of the luma/chroma/hue bicone.
    // The hue plane is a triangle.
    // This bicone is distorted, so we can not simply mirror the triangle.
    // We need to stretch it to a luma/saturation rectangle, so we need to stretch chroma C and the proportional X.

    // First, we need to calculate luma Y_full_C for the outer corner of the triangle.
    // Then we can interpolate the max chroma C_max, C_inv_max for our luma Y, Y_inv.
    // Then we calculate C_inv and X_inv by scaling them by the ratio of C_max and C_inv_max.

    // Calculate luma Y_full_C (in range equivalent to gray 0..255) for chroma = 1 at this hue.
    // Piecewise linear, with the corners of the bicone at the sum of one or two luma coefficients.
    float Y_full_C;
    if (R >= B && B >= G) {
        Y_full_C = 255 * Y_R + 255 * Y_B * B / R;
    } else if (R >= G && G >= B) {
        Y_full_C = 255 * Y_R + 255 * Y_G * G / R;
    } else if (G >= R && R >= B) {
        Y_full_C = 255 * Y_G + 255 * Y_R * R / G;
    } else if (G >= B && B >= R) {
        Y_full_C = 255 * Y_G + 255 * Y_B * B / G;
    } else if (B >= G && G >= R) {
        Y_full_C = 255 * Y_B + 255 * Y_G * G / B;
    } else {
        Y_full_C = 255 * Y_B + 255 * Y_R * R / B;
    }

    // Calculate C_max, C_inv_max, to scale C and X.
    float C_max, C_inv_max;
    if (Y >= Y_full_C) {
        C_max = Y_inv / (255 - Y_full_C);
    } else {
        C_max = Y / Y_full_C;
    }
    if (Y_inv >= Y_full_C) {
        C_inv_max = Y / (255 - Y_full_C);
    } else {
        C_inv_max = Y_inv / Y_full_C;
    }

    // Scale C and X. C and X already lie in R, G, B.
    float C_scale = C_inv_max / C_max;
    float R_ = R * C_scale;
    float G_ = G * C_scale;
    float B_ = B * C_scale;

    // Calculate missing luma (in range 0..255), to get common component m_inv
    float m_inv = Y_inv - (Y_R * R_ + Y_G * G_ + Y_B * B_);

    // Add m_inv to color compontents
    R_ += m_inv;
    G_ += m_inv;
    B_ += m_inv;

    // Return colors rounded
    R = R_ + 0.5;
    G = G_ + 0.5;
    B = B_ + 0.5;
}

void PagePainter::hueShiftPositive(QImage* image)
{
    if (image->format() != QImage::Format_ARGB32_Premultiplied) {
        qCWarning(OkularUiDebug) << "Wrong image format! Converting...";
        *image = image->convertToFormat(QImage::Format_ARGB32_Premultiplied);
    }

    Q_ASSERT(image->format() == QImage::Format_ARGB32_Premultiplied);

    QRgb * data = reinterpret_cast<QRgb*>(image->bits());
    int pixels = image->width() * image->height();
    for ( int i = 0; i < pixels; ++i )
    {
        uchar R = qRed( data[ i ] );
        uchar G = qGreen( data[ i ] );
        uchar B = qBlue( data[ i ] );

        // Save new color
        data[i] = qRgba( B, R, G, 255 );
    }
}

void PagePainter::hueShiftNegative(QImage* image)
{
    if (image->format() != QImage::Format_ARGB32_Premultiplied) {
        qCWarning(OkularUiDebug) << "Wrong image format! Converting...";
        *image = image->convertToFormat(QImage::Format_ARGB32_Premultiplied);
    }

    Q_ASSERT(image->format() == QImage::Format_ARGB32_Premultiplied);

    QRgb * data = reinterpret_cast<QRgb*>(image->bits());
    int pixels = image->width() * image->height();
    for ( int i = 0; i < pixels; ++i )
    {
        uchar R = qRed( data[ i ] );
        uchar G = qGreen( data[ i ] );
        uchar B = qBlue( data[ i ] );

        // Save new color
        data[i] = qRgba( G, B, R, 255 );
    }
}

/** Private Helpers :: Image Drawing **/
// from Arthur - qt4
static inline int qt_div_255(int x) { return (x + (x>>8) + 0x80) >> 8; }

void PagePainter::changeImageAlpha( QImage & image, unsigned int destAlpha )
{
    image = image.convertToFormat(QImage::Format_ARGB32);
    // iterate over all pixels changing the alpha component value
    unsigned int * data = reinterpret_cast<unsigned int *>(image.bits());
    unsigned int pixels = image.width() * image.height();

    int source, sourceAlpha;
    for( unsigned int i = 0; i < pixels; ++i )
    {   // optimize this loop keeping byte order into account
        source = data[i];
        if ( (sourceAlpha = qAlpha( source )) == 255 )
        {
            // use destAlpha
            data[i] = qRgba( qRed(source), qGreen(source), qBlue(source), destAlpha );
        }
        else
        {
            // use destAlpha * sourceAlpha product
            sourceAlpha = qt_div_255( destAlpha * sourceAlpha );
            data[i] = qRgba( qRed(source), qGreen(source), qBlue(source), sourceAlpha );
        }
    }
}

void PagePainter::drawShapeOnImage(
    QImage & image,
    const NormalizedPath & normPath,
    bool closeShape,
    const QPen & pen,
    const QBrush & brush,
    double penWidthMultiplier,
    RasterOperation op
    //float antiAliasRadius
    )
{
    // safety checks
    int pointsNumber = normPath.size();
    if ( pointsNumber < 2 )
        return;

    int imageWidth = image.width();
    int imageHeight = image.height();
    double fImageWidth = (double)imageWidth;
    double fImageHeight = (double)imageHeight;

    // stroke outline
    double penWidth = (double)pen.width() * penWidthMultiplier;
    QPainter painter(&image);
    painter.setRenderHint(QPainter::Antialiasing);
    QPen pen2 = pen;
    pen2.setWidthF(penWidth);
    painter.setPen(pen2);
    painter.setBrush(brush);

    if (op == Multiply) {
        painter.setCompositionMode(QPainter::CompositionMode_Multiply);
    }

    if ( brush.style() == Qt::NoBrush )
    {
        // create a polygon
        QPolygonF poly( closeShape ? pointsNumber + 1 : pointsNumber );
        for ( int i = 0; i < pointsNumber; ++i )
        {
            poly[ i ] = QPointF( normPath[ i ].x * fImageWidth, normPath[ i ].y * fImageHeight );
        }
        if ( closeShape )
            poly[ pointsNumber ] = poly[ 0 ];

        painter.drawPolyline( poly );
    }
    else
    {
        // create a 'path'
        QPainterPath path;
        path.setFillRule( Qt::WindingFill );

        path.moveTo( normPath[ 0 ].x * fImageWidth, normPath[ 0 ].y * fImageHeight );
        for ( int i = 1; i < pointsNumber; i++ )
        {
            path.lineTo( normPath[ i ].x * fImageWidth, normPath[ i ].y * fImageHeight );
        }
        if ( closeShape )
            path.closeSubpath();

        painter.drawPath( path );
    }
}

void PagePainter::drawEllipseOnImage(
    QImage & image,
    const NormalizedPath & rect,
    const QPen & pen,
    const QBrush & brush,
    double penWidthMultiplier,
    RasterOperation op
    )
{
    const double fImageWidth = (double) image.width();
    const double fImageHeight = (double) image.height();

    // stroke outline
    const double penWidth = (double)pen.width() * penWidthMultiplier;
    QPainter painter(&image);
    painter.setRenderHint(QPainter::Antialiasing);
    QPen pen2 = pen;
    pen2.setWidthF(penWidth);
    painter.setPen(pen2);
    painter.setBrush(brush);

    if ( op == Multiply ) {
        painter.setCompositionMode(QPainter::CompositionMode_Multiply);
    }

    const QPointF &topLeft { rect[0].x * fImageWidth, rect[0].y * fImageHeight };
    const QSizeF &size { (rect[1].x - rect[0].x) * fImageWidth, (rect[1].y - rect[0].y) * fImageHeight };
    const QRectF imgRect { topLeft, size };
    if ( brush.style() == Qt::NoBrush )
    {
        painter.drawArc( imgRect, 0, 16*360 );
    } else {
        painter.drawEllipse( imgRect );
    }
}

LineAnnotPainter::LineAnnotPainter( const Okular::LineAnnotation * a, QSizeF pageSize, double pageScale, const QTransform &toNormalizedImage )
    : la { a }
    , pageSize { pageSize }
    , pageScale { pageScale }
    , toNormalizedImage { toNormalizedImage }
    , aspectRatio { pageSize.height() / pageSize.width() }
    , linePen { buildPen( a, a->style().width(), a->style().color() ) }
{
    if ( ( la->lineClosed() || la->transformedLinePoints().count() == 2 ) &&
        la->lineInnerColor().isValid() )
    {
        fillBrush = QBrush( la->lineInnerColor() );
    }
}

void LineAnnotPainter::draw( QImage &image ) const
{
    const QLinkedList<Okular::NormalizedPoint> transformedLinePoints = la->transformedLinePoints();
    if ( transformedLinePoints.count() == 2 )
    {
        const Okular::NormalizedPoint delta {
            transformedLinePoints.last().x - transformedLinePoints.first().x,
            transformedLinePoints.first().y - transformedLinePoints.last().y
        };
        const double angle { atan2( delta.y * aspectRatio, delta.x ) };
        const double cosA { cos( -angle ) };
        const double sinA { sin( -angle ) };
        const QTransform tmpMatrix = QTransform {
            cosA, sinA / aspectRatio,
            -sinA, cosA / aspectRatio,
            transformedLinePoints.first().x,
            transformedLinePoints.first().y };
        const double deaspectedY { delta.y * aspectRatio };
        const double mainSegmentLength { sqrt( delta.x * delta.x + deaspectedY * deaspectedY ) };
        const double lineendSize { std::min( 6. * la->style().width() / pageSize.width(), mainSegmentLength / 2. ) };

        drawShortenedLine( mainSegmentLength, lineendSize, image, tmpMatrix );
        drawLineEnds( mainSegmentLength, lineendSize, image, tmpMatrix );
        drawLeaderLine( 0., image, tmpMatrix );
        drawLeaderLine( mainSegmentLength, image, tmpMatrix );
    }
    else if ( transformedLinePoints.count() > 2 )
    {
        drawMainLine( image );
    }
}

void LineAnnotPainter::drawMainLine( QImage &image ) const
{
    // draw the line as normalized path into image
    PagePainter::drawShapeOnImage( image, transformPath(
        la->transformedLinePoints(), toNormalizedImage ), la->lineClosed(),
        linePen, fillBrush, pageScale, PagePainter::Multiply );
}

void LineAnnotPainter::drawShortenedLine( double mainSegmentLength, double size, QImage &image, const QTransform& toNormalizedPage ) const
{
    const QTransform combinedTransform { toNormalizedPage * toNormalizedImage };
    const QList<Okular::NormalizedPoint> path {
        { shortenForArrow(size, la->lineStartStyle()), 0 },
        { mainSegmentLength - shortenForArrow(size, la->lineEndStyle()), 0 }
    };
    PagePainter::drawShapeOnImage( image, transformPath(path, combinedTransform),
        la->lineClosed(), linePen, fillBrush, pageScale, PagePainter::Multiply );
}

void LineAnnotPainter::drawLineEnds( double mainSegmentLength, double size, QImage &image, const QTransform& transform ) const
{
    switch ( la->lineStartStyle() ) {
    case Okular::LineAnnotation::Square:
        drawLineEndSquare( 0, -size, transform, image );
        break;
    case Okular::LineAnnotation::Circle:
        drawLineEndCircle( 0, -size, transform, image );
        break;
    case Okular::LineAnnotation::Diamond:
        drawLineEndDiamond( 0, -size, transform, image );
        break;
    case Okular::LineAnnotation::OpenArrow:
        drawLineEndArrow( 0, -size, 1., false, transform, image );
        break;
    case Okular::LineAnnotation::ClosedArrow:
        drawLineEndArrow( 0, -size, 1., true, transform, image );
        break;
    case Okular::LineAnnotation::None:
        break;
    case Okular::LineAnnotation::Butt:
        drawLineEndButt( 0, size, transform, image );
        break;
    case Okular::LineAnnotation::ROpenArrow:
        drawLineEndArrow( 0, size, 1., false, transform, image );
        break;
    case Okular::LineAnnotation::RClosedArrow:
        drawLineEndArrow( 0, size, 1., true, transform, image );
        break;
    case Okular::LineAnnotation::Slash:
        drawLineEndSlash( 0, -size, transform, image );
        break;
    }
    switch ( la->lineEndStyle() ) {
    case Okular::LineAnnotation::Square:
        drawLineEndSquare( mainSegmentLength, size, transform, image );
        break;
    case Okular::LineAnnotation::Circle:
        drawLineEndCircle( mainSegmentLength, size, transform, image );
        break;
    case Okular::LineAnnotation::Diamond:
        drawLineEndDiamond( mainSegmentLength, size, transform, image );
        break;
    case Okular::LineAnnotation::OpenArrow:
        drawLineEndArrow( mainSegmentLength, size, 1., false, transform, image );
        break;
    case Okular::LineAnnotation::ClosedArrow:
        drawLineEndArrow( mainSegmentLength, size, 1., true, transform, image );
        break;
    case Okular::LineAnnotation::None:
        break;
    case Okular::LineAnnotation::Butt:
        drawLineEndButt( mainSegmentLength, size, transform, image );
        break;
    case Okular::LineAnnotation::ROpenArrow:
        drawLineEndArrow( mainSegmentLength, size, -1., false, transform, image );
        break;
    case Okular::LineAnnotation::RClosedArrow:
        drawLineEndArrow( mainSegmentLength, size, -1., true, transform, image );
        break;
    case Okular::LineAnnotation::Slash:
        drawLineEndSlash( mainSegmentLength, size, transform, image );
        break;
    }
}

void LineAnnotPainter::drawLineEndArrow( double xEndPos, double size, double flipX, bool close, const QTransform& toNormalizedPage, QImage &image ) const
{
    const QTransform combinedTransform { toNormalizedPage * toNormalizedImage };
    const QList<Okular::NormalizedPoint> path {
        { xEndPos - size * flipX, size / 2. },
        { xEndPos, 0 },
        { xEndPos - size * flipX, -size / 2. },
    };
    PagePainter::drawShapeOnImage( image, transformPath(path, combinedTransform),
        close, linePen, fillBrush, pageScale, PagePainter::Multiply);
}

void LineAnnotPainter::drawLineEndButt( double xEndPos, double size, const QTransform& toNormalizedPage, QImage &image ) const
{
    const QTransform combinedTransform { toNormalizedPage * toNormalizedImage };
    const double halfSize { size / 2. };
    const QList<Okular::NormalizedPoint> path {
        { xEndPos, halfSize },
        { xEndPos, -halfSize },
    };
    PagePainter::drawShapeOnImage( image, transformPath(path, combinedTransform),
        true, linePen, fillBrush, pageScale, PagePainter::Multiply);
}

void LineAnnotPainter::drawLineEndCircle( double xEndPos, double size, const QTransform& toNormalizedPage, QImage &image ) const
{
    /* transform the circle midpoint to intermediate normalized coordinates
     * where it's easy to construct the bounding rect of the circle */
    Okular::NormalizedPoint center;
    toNormalizedPage.map( xEndPos - size / 2., 0, &center.x, &center.y );
    const double halfSize { size / 2. };
    const QList<Okular::NormalizedPoint> path {
        { center.x - halfSize, center.y - halfSize / aspectRatio },
        { center.x + halfSize, center.y + halfSize / aspectRatio },
    };

    /* then transform bounding rect with toNormalizedImage */
    PagePainter::drawEllipseOnImage(
        image,
        transformPath(path, toNormalizedImage),
        linePen,
        fillBrush,
        pageScale,
        PagePainter::Multiply);
}

void LineAnnotPainter::drawLineEndSquare( double xEndPos, double size, const QTransform& toNormalizedPage, QImage &image ) const
{
    const QTransform combinedTransform { toNormalizedPage * toNormalizedImage };
    const QList<Okular::NormalizedPoint> path {
        { xEndPos, size / 2. },
        { xEndPos - size, size / 2. },
        { xEndPos - size, -size / 2. },
        { xEndPos, -size / 2. }
    };
    PagePainter::drawShapeOnImage( image, transformPath(path, combinedTransform),
        true, linePen, fillBrush, pageScale, PagePainter::Multiply);
}

void LineAnnotPainter::drawLineEndDiamond( double xEndPos, double size, const QTransform& toNormalizedPage, QImage &image ) const
{
    const QTransform combinedTransform { toNormalizedPage * toNormalizedImage };
    const QList<Okular::NormalizedPoint> path {
        { xEndPos, 0 },
        { xEndPos - size / 2., size / 2. },
        { xEndPos - size, 0 },
        { xEndPos - size / 2., -size / 2. }
    };
    PagePainter::drawShapeOnImage( image, transformPath(path, combinedTransform),
        true, linePen, fillBrush, pageScale, PagePainter::Multiply);
}

void LineAnnotPainter::drawLineEndSlash( double xEndPos, double size, const QTransform& toNormalizedPage, QImage &image ) const
{
    const QTransform combinedTransform { toNormalizedPage * toNormalizedImage };
    const double halfSize { size / 2. };
    const double xOffset { cos(M_PI/3.) * halfSize };
    const QList<Okular::NormalizedPoint> path {
        { xEndPos - xOffset, halfSize },
        { xEndPos + xOffset, -halfSize },
    };
    PagePainter::drawShapeOnImage( image, transformPath(path, combinedTransform),
        true, linePen, fillBrush, pageScale, PagePainter::Multiply);
}

void LineAnnotPainter::drawLeaderLine( double xEndPos, QImage &image, const QTransform& toNormalizedPage ) const
{
    const QTransform combinedTransform = toNormalizedPage * toNormalizedImage;
    const double ll = aspectRatio * la->lineLeadingForwardPoint() / pageSize.height();
    const double lle = aspectRatio * la->lineLeadingBackwardPoint() / pageSize.height();
    const int sign { ll > 0 ? -1 : 1 };
    QList<Okular::NormalizedPoint> path;

    if ( fabs( ll ) > 0 ) {
        path.append( { xEndPos, ll } );
        // do we have the extension on the "back"?
        if ( fabs( lle ) > 0 )
        {
            path.append( { xEndPos, sign * lle } );
        } else {
            path.append( { xEndPos, 0 } );
        }
    }
    PagePainter::drawShapeOnImage( image, transformPath(path, combinedTransform), false,
        linePen, fillBrush, pageScale, PagePainter::Multiply);
}

double LineAnnotPainter::shortenForArrow( double size, Okular::LineAnnotation::TermStyle endStyle )
{
    double shortenBy { 0 };

    if ( endStyle == Okular::LineAnnotation::Square ||
         endStyle == Okular::LineAnnotation::Circle ||
         endStyle == Okular::LineAnnotation::Diamond ||
         endStyle == Okular::LineAnnotation::ClosedArrow )
    {
        shortenBy = size;
    }

    return shortenBy;
}

/* kate: replace-tabs on; indent-width 4; */

